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<h1 class="entry-title">.focusin()</h1>
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						所属分类：<span class="category"><a href="/category/events/">事件</a> &gt; <a href="/category/events/form-events/">表单事件</a></span><span class="category-divider"> | </span><span class="category"><a href="/category/forms/">表单</a></span>
<span class="pull-right">英文文档：<a href="https://api.jquery123.com/focusin/" target="_blank">.focusin()</a></span>
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<span class="name">.focusin( handler(eventObject) )</span><span class="returns">返回: <a href="/Types/#jQuery">jQuery</a></span>
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<p class="desc"><strong>描述: </strong>将一个事件函数绑定到"focusin" 事件。</p>
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<span class="version-details">添加的版本: <a href="/category/version/1.4/">1.4</a></span>.focusin( handler(eventObject) )</h4>
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<div><strong>handler(eventObject)</strong></div>
<div>类型: <a href="/Types/#Function">Function</a>()</div>
<div>每次事件触发时会执行的函数。</div>
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<span class="version-details">添加的版本: <a href="/category/version/1.4.3/">1.4.3</a></span>.focusin(  [eventData ], handler(eventObject) )</h4>
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<div><strong>eventData</strong></div>
<div>类型: <a href="/Types/#Object">Object</a>
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<div>一个对象，它包含的数据键值对映射将被传递给事件处理程序。</div>
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<div><strong>handler(eventObject)</strong></div>
<div>类型: <a href="/Types/#Function">Function</a>()</div>
<div>每次事件触发时会执行的函数。</div>
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<p>这个方法是 <code>.bind('focusin', handler)</code> 的快捷方式。</p>
<p><code>focusin</code> 事件会在元素（或者其内部的任何元素）获得焦点时触发。这跟 <a href="/focus">focus</a> 事件的显著区别在于，它可以在父元素上检测子元素获得焦点的情况(换而言之，它支持事件冒泡)。</p>
<p>此事件通常会和<a href="/focusout">focusout</a>事件一起使用。</p>
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<section class="entry-examples" id="entry-examples"><header><h2 class="underline">例子:</h2></header><div class="entry-example" id="example-0">
<h4><span class="desc">监控页面上段落内获得焦点的情况。</span></h4>
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<pre><div class="container"><div class="line"><code><span class="doctype">&lt;!DOCTYPE html&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">html</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">head</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>  <span class="tag">&lt;<span class="title">style</span>&gt;</span><span class="css"><span class="tag">span</span> <span class="rules">{<span class="rule"><span class="attribute">display</span>:<span class="value">none;</span></span><span class="rule">}</span></span></span><span class="tag">&lt;/<span class="title">style</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>  <span class="tag">&lt;<span class="title">script</span> <span class="attribute">src</span>=<span class="value">"https://code.jquery.com/jquery-latest.js"</span>&gt;</span><span class="javascript"></span><span class="tag">&lt;/<span class="title">script</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">head</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">body</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>  <span class="tag">&lt;<span class="title">p</span>&gt;</span><span class="tag">&lt;<span class="title">input</span> <span class="attribute">type</span>=<span class="value">"text"</span> /&gt;</span> <span class="tag">&lt;<span class="title">span</span>&gt;</span>focusin fire<span class="tag">&lt;/<span class="title">span</span>&gt;</span><span class="tag">&lt;/<span class="title">p</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">p</span>&gt;</span><span class="tag">&lt;<span class="title">input</span> <span class="attribute">type</span>=<span class="value">"password"</span> /&gt;</span> <span class="tag">&lt;<span class="title">span</span>&gt;</span>focusin fire<span class="tag">&lt;/<span class="title">span</span>&gt;</span><span class="tag">&lt;/<span class="title">p</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">script</span>&gt;</span><span class="javascript"></span></code></div></div><div class="container"><div class="line"><code>$(<span class="string">"p"</span>).focusin(<span class="keyword">function</span>() {</code></div></div><div class="container"><div class="line"><code>  $(<span class="keyword">this</span>).find(<span class="string">"span"</span>).css(<span class="string">'display'</span>,<span class="string">'inline'</span>).fadeOut(<span class="number">1000</span>);</code></div></div><div class="container"><div class="line"><code>});</code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">script</span>&gt;</span></code></div></div><div class="container"><div class="line"><code> </code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">body</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">html</span>&gt;</span></code></div></div></pre>
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<h4>Demo:</h4>
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